Undeprecate PIL int constants for interpolation (#7241)

Author: pmeier

test/test_functional_tensor.py

@@ -7,6 +7,7 @@
 from typing import Sequence
 
 import numpy as np
+import PIL.Image
 import pytest
 import torch
 import torchvision.transforms as T
@@ -144,6 +145,12 @@ def test_rotate_batch(self, device, dt):
         center = (20, 22)
         _test_fn_on_batch(batch_tensors, F.rotate, angle=32, interpolation=NEAREST, expand=True, center=center)
 
+    def test_rotate_interpolation_type(self):
+        tensor, _ = _create_data(26, 26)
+        res1 = F.rotate(tensor, 45, interpolation=PIL.Image.BILINEAR)
+        res2 = F.rotate(tensor, 45, interpolation=BILINEAR)
+        assert_equal(res1, res2)
+
 
 class TestAffine:
 
@@ -350,6 +357,14 @@ def test_batches(self, device, dt):
 
         _test_fn_on_batch(batch_tensors, F.affine, angle=-43, translate=[-3, 4], scale=1.2, shear=[4.0, 5.0])
 
+    @pytest.mark.parametrize("device", cpu_and_gpu())
+    def test_interpolation_type(self, device):
+        tensor, pil_img = _create_data(26, 26, device=device)
+
+        res1 = F.affine(tensor, 45, translate=[0, 0], scale=1.0, shear=[0.0, 0.0], interpolation=PIL.Image.BILINEAR)
+        res2 = F.affine(tensor, 45, translate=[0, 0], scale=1.0, shear=[0.0, 0.0], interpolation=BILINEAR)
+        assert_equal(res1, res2)
+
 
 def _get_data_dims_and_points_for_perspective():
     # Ideally we would parametrize independently over data dims and points, but
@@ -448,6 +463,16 @@ def test_perspective_batch(device, dims_and_points, dt):
     )
 
 
+def test_perspective_interpolation_type():
+    spoints = [[0, 0], [33, 0], [33, 25], [0, 25]]
+    epoints = [[3, 2], [32, 3], [30, 24], [2, 25]]
+    tensor = torch.randint(0, 256, (3, 26, 26))
+
+    res1 = F.perspective(tensor, startpoints=spoints, endpoints=epoints, interpolation=PIL.Image.BILINEAR)
+    res2 = F.perspective(tensor, startpoints=spoints, endpoints=epoints, interpolation=BILINEAR)
+    assert_equal(res1, res2)
+
+
 @pytest.mark.parametrize("device", cpu_and_gpu())
 @pytest.mark.parametrize("dt", [None, torch.float32, torch.float64, torch.float16])
 @pytest.mark.parametrize(
@@ -489,9 +514,7 @@ def test_resize(device, dt, size, max_size, interpolation):
 
     assert resized_tensor.size()[1:] == resized_pil_img.size[::-1]
 
-    if interpolation not in [
-        NEAREST,
-    ]:
+    if interpolation != NEAREST:
         # We can not check values if mode = NEAREST, as results are different
         # E.g. resized_tensor  = [[a, a, b, c, d, d, e, ...]]
         # E.g. resized_pil_img = [[a, b, c, c, d, e, f, ...]]
@@ -504,9 +527,7 @@ def test_resize(device, dt, size, max_size, interpolation):
         _assert_approx_equal_tensor_to_pil(resized_tensor_f, resized_pil_img, tol=8.0)
 
     if isinstance(size, int):
-        script_size = [
-            size,
-        ]
+        script_size = [size]
     else:
         script_size = size
 
@@ -523,6 +544,10 @@ def test_resize_asserts(device):
 
     tensor, pil_img = _create_data(26, 36, device=device)
 
+    res1 = F.resize(tensor, size=32, interpolation=PIL.Image.BILINEAR)
+    res2 = F.resize(tensor, size=32, interpolation=BILINEAR)
+    assert_equal(res1, res2)
+
     for img in (tensor, pil_img):
         exp_msg = "max_size should only be passed if size specifies the length of the smaller edge"
         with pytest.raises(ValueError, match=exp_msg):

test/test_onnx.py

@@ -407,13 +407,12 @@ def forward(self_module, images, features):
     def get_image(self, rel_path: str, size: Tuple[int, int]) -> torch.Tensor:
         import os
 
-        import torchvision.transforms._pil_constants as _pil_constants
         from PIL import Image
         from torchvision.transforms import functional as F
 
         data_dir = os.path.join(os.path.dirname(__file__), "assets")
         path = os.path.join(data_dir, *rel_path.split("/"))
-        image = Image.open(path).convert("RGB").resize(size, _pil_constants.BILINEAR)
+        image = Image.open(path).convert("RGB").resize(size, Image.BILINEAR)
 
         return F.convert_image_dtype(F.pil_to_tensor(image))
 

test/test_transforms.py

@@ -9,7 +9,6 @@
 import pytest
 import torch
 import torchvision.transforms as transforms
-import torchvision.transforms._pil_constants as _pil_constants
 import torchvision.transforms.functional as F
 import torchvision.transforms.functional_tensor as F_t
 from PIL import Image
@@ -175,7 +174,7 @@ def test_accimage_pil_to_tensor(self):
     def test_accimage_resize(self):
         trans = transforms.Compose(
             [
-                transforms.Resize(256, interpolation=_pil_constants.LINEAR),
+                transforms.Resize(256, interpolation=Image.LINEAR),
                 transforms.PILToTensor(),
                 transforms.ConvertImageDtype(dtype=torch.float),
             ]
@@ -1533,10 +1532,10 @@ def test_ten_crop(should_vflip, single_dim):
     five_crop.__repr__()
 
     if should_vflip:
-        vflipped_img = img.transpose(_pil_constants.FLIP_TOP_BOTTOM)
+        vflipped_img = img.transpose(Image.FLIP_TOP_BOTTOM)
         expected_output += five_crop(vflipped_img)
     else:
-        hflipped_img = img.transpose(_pil_constants.FLIP_LEFT_RIGHT)
+        hflipped_img = img.transpose(Image.FLIP_LEFT_RIGHT)
         expected_output += five_crop(hflipped_img)
 
     assert len(results) == 10
@@ -1883,6 +1882,9 @@ def test_random_rotation():
     # Checking if RandomRotation can be printed as string
     t.__repr__()
 
+    t = transforms.RandomRotation((-10, 10), interpolation=Image.BILINEAR)
+    assert t.interpolation == transforms.InterpolationMode.BILINEAR
+
 
 def test_random_rotation_error():
     # assert fill being either a Sequence or a Number
@@ -2212,6 +2214,9 @@ def test_random_affine():
     t = transforms.RandomAffine(10, interpolation=transforms.InterpolationMode.BILINEAR)
     assert "bilinear" in t.__repr__()
 
+    t = transforms.RandomAffine(10, interpolation=Image.BILINEAR)
+    assert t.interpolation == transforms.InterpolationMode.BILINEAR
+
 
 def test_elastic_transformation():
     with pytest.raises(TypeError, match=r"alpha should be float or a sequence of floats"):
@@ -2228,9 +2233,8 @@ def test_elastic_transformation():
     with pytest.raises(ValueError, match=r"sigma is a sequence its length should be 2"):
         transforms.ElasticTransform(alpha=2.0, sigma=[1.0, 0.0, 1.0])
 
-    with pytest.warns(UserWarning, match=r"Argument interpolation should be of type InterpolationMode"):
-        t = transforms.transforms.ElasticTransform(alpha=2.0, sigma=2.0, interpolation=2)
-        assert t.interpolation == transforms.InterpolationMode.BILINEAR
+    t = transforms.transforms.ElasticTransform(alpha=2.0, sigma=2.0, interpolation=Image.BILINEAR)
+    assert t.interpolation == transforms.InterpolationMode.BILINEAR
 
     with pytest.raises(TypeError, match=r"fill should be int or float"):
         transforms.ElasticTransform(alpha=1.0, sigma=1.0, fill={})

test/test_transforms_tensor.py

@@ -3,9 +3,9 @@
 import warnings
 
 import numpy as np
+import PIL.Image
 import pytest
 import torch
-import torchvision.transforms._pil_constants as _pil_constants
 from common_utils import (
     _assert_approx_equal_tensor_to_pil,
     _assert_equal_tensor_to_pil,
@@ -657,13 +657,13 @@ def shear(pil_img, level, mode, resample):
             matrix = (1, level, 0, 0, 1, 0)
         elif mode == "Y":
             matrix = (1, 0, 0, level, 1, 0)
-        return pil_img.transform((image_size, image_size), _pil_constants.AFFINE, matrix, resample=resample)
+        return pil_img.transform((image_size, image_size), PIL.Image.AFFINE, matrix, resample=resample)
 
     t_img, pil_img = _create_data(image_size, image_size)
 
     resample_pil = {
-        F.InterpolationMode.NEAREST: _pil_constants.NEAREST,
-        F.InterpolationMode.BILINEAR: _pil_constants.BILINEAR,
+        F.InterpolationMode.NEAREST: PIL.Image.NEAREST,
+        F.InterpolationMode.BILINEAR: PIL.Image.BILINEAR,
     }[interpolation]
 
     level = 0.3

torchvision/transforms/_pil_constants.py

@@ -421,6 +421,7 @@ def resize(
             Default is ``InterpolationMode.BILINEAR``. If input is Tensor, only ``InterpolationMode.NEAREST``,
             ``InterpolationMode.NEAREST_EXACT``, ``InterpolationMode.BILINEAR`` and ``InterpolationMode.BICUBIC`` are
             supported.
+            The corresponding Pillow integer constants, e.g. ``PIL.Image.BILINEAR`` are accepted as well.
         max_size (int, optional): The maximum allowed for the longer edge of
             the resized image: if the longer edge of the image is greater
             than ``max_size`` after being resized according to ``size``, then
@@ -454,8 +455,12 @@ def resize(
     if not torch.jit.is_scripting() and not torch.jit.is_tracing():
         _log_api_usage_once(resize)
 
-    if not isinstance(interpolation, InterpolationMode):
-        raise TypeError("Argument interpolation should be a InterpolationMode")
+    if isinstance(interpolation, int):
+        interpolation = _interpolation_modes_from_int(interpolation)
+    elif not isinstance(interpolation, InterpolationMode):
+        raise TypeError(
+            "Argument interpolation should be a InterpolationMode or a corresponding Pillow integer constant"
+        )
 
     if isinstance(size, (list, tuple)):
         if len(size) not in [1, 2]:
@@ -630,6 +635,7 @@ def resized_crop(
             Default is ``InterpolationMode.BILINEAR``. If input is Tensor, only ``InterpolationMode.NEAREST``,
             ``InterpolationMode.NEAREST_EXACT``, ``InterpolationMode.BILINEAR`` and ``InterpolationMode.BICUBIC`` are
             supported.
+            The corresponding Pillow integer constants, e.g. ``PIL.Image.BILINEAR`` are accepted as well.
         antialias (bool, optional): Whether to apply antialiasing.
             It only affects **tensors** with bilinear or bicubic modes and it is
             ignored otherwise: on PIL images, antialiasing is always applied on
@@ -726,6 +732,7 @@ def perspective(
         interpolation (InterpolationMode): Desired interpolation enum defined by
             :class:`torchvision.transforms.InterpolationMode`. Default is ``InterpolationMode.BILINEAR``.
             If input is Tensor, only ``InterpolationMode.NEAREST``, ``InterpolationMode.BILINEAR`` are supported.
+            The corresponding Pillow integer constants, e.g. ``PIL.Image.BILINEAR`` are accepted as well.
         fill (sequence or number, optional): Pixel fill value for the area outside the transformed
             image. If given a number, the value is used for all bands respectively.
 
@@ -741,8 +748,12 @@ def perspective(
 
     coeffs = _get_perspective_coeffs(startpoints, endpoints)
 
-    if not isinstance(interpolation, InterpolationMode):
-        raise TypeError("Argument interpolation should be a InterpolationMode")
+    if isinstance(interpolation, int):
+        interpolation = _interpolation_modes_from_int(interpolation)
+    elif not isinstance(interpolation, InterpolationMode):
+        raise TypeError(
+            "Argument interpolation should be a InterpolationMode or a corresponding Pillow integer constant"
+        )
 
     if not isinstance(img, torch.Tensor):
         pil_interpolation = pil_modes_mapping[interpolation]
@@ -1076,6 +1087,7 @@ def rotate(
         interpolation (InterpolationMode): Desired interpolation enum defined by
             :class:`torchvision.transforms.InterpolationMode`. Default is ``InterpolationMode.NEAREST``.
             If input is Tensor, only ``InterpolationMode.NEAREST``, ``InterpolationMode.BILINEAR`` are supported.
+            The corresponding Pillow integer constants, e.g. ``PIL.Image.BILINEAR`` are accepted as well.
         expand (bool, optional): Optional expansion flag.
             If true, expands the output image to make it large enough to hold the entire rotated image.
             If false or omitted, make the output image the same size as the input image.
@@ -1097,15 +1109,19 @@ def rotate(
     if not torch.jit.is_scripting() and not torch.jit.is_tracing():
         _log_api_usage_once(rotate)
 
+    if isinstance(interpolation, int):
+        interpolation = _interpolation_modes_from_int(interpolation)
+    elif not isinstance(interpolation, InterpolationMode):
+        raise TypeError(
+            "Argument interpolation should be a InterpolationMode or a corresponding Pillow integer constant"
+        )
+
     if not isinstance(angle, (int, float)):
         raise TypeError("Argument angle should be int or float")
 
     if center is not None and not isinstance(center, (list, tuple)):
         raise TypeError("Argument center should be a sequence")
 
-    if not isinstance(interpolation, InterpolationMode):
-        raise TypeError("Argument interpolation should be a InterpolationMode")
-
     if not isinstance(img, torch.Tensor):
         pil_interpolation = pil_modes_mapping[interpolation]
         return F_pil.rotate(img, angle=angle, interpolation=pil_interpolation, expand=expand, center=center, fill=fill)
@@ -1147,6 +1163,7 @@ def affine(
         interpolation (InterpolationMode): Desired interpolation enum defined by
             :class:`torchvision.transforms.InterpolationMode`. Default is ``InterpolationMode.NEAREST``.
             If input is Tensor, only ``InterpolationMode.NEAREST``, ``InterpolationMode.BILINEAR`` are supported.
+            The corresponding Pillow integer constants, e.g. ``PIL.Image.BILINEAR`` are accepted as well.
         fill (sequence or number, optional): Pixel fill value for the area outside the transformed
             image. If given a number, the value is used for all bands respectively.
 
@@ -1162,6 +1179,13 @@ def affine(
     if not torch.jit.is_scripting() and not torch.jit.is_tracing():
         _log_api_usage_once(affine)
 
+    if isinstance(interpolation, int):
+        interpolation = _interpolation_modes_from_int(interpolation)
+    elif not isinstance(interpolation, InterpolationMode):
+        raise TypeError(
+            "Argument interpolation should be a InterpolationMode or a corresponding Pillow integer constant"
+        )
+
     if not isinstance(angle, (int, float)):
         raise TypeError("Argument angle should be int or float")
 
@@ -1177,9 +1201,6 @@ def affine(
     if not isinstance(shear, (numbers.Number, (list, tuple))):
         raise TypeError("Shear should be either a single value or a sequence of two values")
 
-    if not isinstance(interpolation, InterpolationMode):
-        raise TypeError("Argument interpolation should be a InterpolationMode")
-
     if isinstance(angle, int):
         angle = float(angle)
 
@@ -1524,7 +1545,7 @@ def elastic_transform(
         interpolation (InterpolationMode): Desired interpolation enum defined by
             :class:`torchvision.transforms.InterpolationMode`.
             Default is ``InterpolationMode.BILINEAR``.
-            For backward compatibility integer values (e.g. ``PIL.Image.NEAREST``) are still acceptable.
+            The corresponding Pillow integer constants, e.g. ``PIL.Image.BILINEAR`` are accepted as well.
         fill (number or str or tuple): Pixel fill value for constant fill. Default is 0.
             If a tuple of length 3, it is used to fill R, G, B channels respectively.
             This value is only used when the padding_mode is constant.